Note on Intermittents
WARNING: This page is about a different car, the 1990 Cadillac Fleetwood and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
If Code E13 is a hard code, start engine and enter diagnostics. Operate engine at fast idle until AUTO closed loop status light is turned on. Observe parameter while manipulating circuits No. 412 and 413 wiring. If parameter P.1.4 changes from fluctuating to fixed at about .45 volt, repair intermittent open circuit.
Check circuit No. 413 ground to engine for proper installation (clean, tight and star washer installed). Ground for circuit No. 413 is attached to rear of right cylinder head.